1. Field of the Invention
This invention relates to a heat-sensitive transferring medium of delayed sending type.
2. Description of the Prior Art
Heat-sensitive transferring recording medium has been recently used widely in place of heat-sensitive color developing paper for the purpose of improving storing durability of recording.
The heat-sensitive transferring recording medium is such that heat is applied to the surface of the medium by means of a thermal head so as to melt the heat-melting ink in the heat-melting ink layer and transfer the molten ink to a receiving paper overlying the medium. The once-used ink sheet is not used again, in usual, and in addition, the heat-sensitive transferring recording mediums are expensive and thereby, the running cost is disadvantageously high.
A proposed improvement is that a substrate of the heat-sensitive transferring recording medium is made in a form of an endless belt and the depleted heat-melting ink due to use is supplemented by coating with a heat-melting ink, but such ink-supplementing device built-in the recording apparatus results in enlarging the recording apparatus, and therefore, the apparatus itself becomes expensive though the running cost is inexpensive.
Another proposed improvement is to employ a heat-melting ink layer composed of a porous layer impregnated with a heat-melting ink. Such heat-melting ink layer can be repeatedly used so that the layer is usually called "multi-type". However, after used once, the heat-sensitive transferring recording medium having the multi-type layer should be rewound and a mechanism for rewinding is necessary.
The present inventors have found that the heat-sensitive transferring recording can be carried out even when the sending speeds of the heat sensitive transferring medium and the receiving paper (a paper receiving the transferred ink for recording) are not the same (i. e. not the speed ratio of 1:1), but the sending speed of the heat sensitive transferring medium is slower than that of the receiving paper.
The sending speeds of them can be easily made different by, for example, adding one gear to a conventional winding-up mechanism for heat-sensitive transferring mediums, or changing the number of tooth of gear even without changing the production line of the apparatus and therefore, the advantage is very large from the stand points of the production and the manufacturing cost.
However, a simply delayed sending of a conventional heat-sensitive transferring medium can not successfully result in good recording since the pressure of the thermal head causes smearing by rubbing.